Tissues and Membranes
Objectives
• Describe the characteristics of each of the four major
categories of tissue.
• Describe the functions of the types of epithelial tissues
• Describe the functions of connective tissue
• Explain the differences between skeletal muscle, smooth
muscle and cardiac muscle.
• Name the 3 parts of the neuron and the function of each.
• Describe locations and types of membranes and the
functions of serous fluid in these locations
• State the location of mucous membranes and the
purpose of mucus.
• Explain the difference between exocrine and endocrine
glands and give an example of each.
Tissues and Membranes
• Four basic tissue types
– Epithelia
– Muscle
– Nervous
– Connective
Epithelia
• Act as linings and
coverings
• Absorption and
secretion
Connective
• Connective and supportive
• Bind body structures together
• Fluid tissue types
– Liquid media for transport, exchange, defense
Muscle
• Ability to contract
• Support
• Movement
Nervous
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•
•
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Conduction
Telecommunications network
Sensory
Motor
Epithelial Tissue
• Found on surfaces
– Coverings of outer surfaces
– Linings of inner surfaces
• Lack capillaries
• Depend on blood supply from supporting
connective tissues
• Many are capable of secretion
Epithelial Tissue
• Classification based:
– on type of cell
– Characteristic shape
– Number of layers of cells
Epithelial Tissue
• Three distinctive shapes
– Squamous
– Cuboidal
– Columnar
• Layers
– Simple= 1 layer
– Stratified= many layers
Simple Squamous Epithelium
• Simple squamous epithelia consist of only a single layer
of flattened cells resting on connective tissues. These
flattened cells are specifically found in thin barriers
where exchange of nutrients, wastes, or respiratory
gases occurs
Simple Cuboidal Epithelia
Due to larger cytoplasmic volumes, cuboidal cells can undertake
more complex functions such as absorption and secretion. Most
secretory cells of glands are cuboidal epithelial cells. In addition, the
ducts of most exocrine glands are lined by cuboidal cells as are
most of the tubules in the kidneys.
Simple Columnar Epithelia
Simple columnar epithelium is found in:
ducts of exocrine glands
larger tubules or collecting ducts of the kidney
stomach, small intestine, and large intestine,
smaller respiratory tubes or bronchioles,
fallopian tubes, Goblet cells
Pseudostratified Epithelium
As the name implies,
pseudostratified epithelium is
"falsely stratified". Cells are
columnar but tall and thin.
All cells rest on the
basement membrane. The
unique appearance of
pseudostratified epithelia
occurs because the tall, thin
cells intertwine. Nuclei
appear at various levels but
there is no distinct layering
Nasal Pseudostratified Epithelium
Stratified Squamous Epithelium
• Many layers
• Lower cells rounded
• Barrier to microorganisms
Stratified Squamous Epithelium
Non-keratinized or mucous type,
stratified squamous is found in:
the oral cavity
Esophagus to the stomach junction
anus and rectum
vagina and cervix
Transitional Epithelium
Transitional
epithelium is only
found in the urinary
tract!
Bladder
Urethra
Stratified Columnar and Cuboidal
Epithlia
Glands
• Organs that secrete something
• Secretion may function at the site of
secretion or at a distant location
• Classified as endocrine or exocrine
Exocrine Glands
• Have ducts
• Connect to the
surface
Modes of Secretion
• Most glands
Modes of Secretion
Modes of Secretion
Endocrine
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•
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Hormone producing
Lack ducts
Hormones enter bloodstream
Circulate throughout body
Target organs
• What kind of gland is the thyroid gland?
• Question: Where is ciliated epithelium
found?
• Question: Where are goblet cells found?
Connective Tissue
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•
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Areolar
Adipose
Fibrous
Elastic
Bone
Blood
Cartilage
Blood
• Cells
– RBC
– Platelets
– WBC
• Plasma
– Transport medium
• What are the functions of the blood cells?
• Question: What other cells are found in
areolar connective tissue, and where is
this tissue found?
• Question: For which organs is adipose
tissue a cushion?
Areolar Connective Tissue
Adipose
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•
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Cells called adipocytes
Store fat
Excess caloric intake stored as fat
Small matrix: tissue fluid and few collagen
fibers
• Stored between dermis and muscle
• Endocrine functions: leptin, estrogen,
cytokines
Fibrous Connective Tissue
• Parallel collagen
fibers
• Few fibroblasts
• Flexible strength
• Poor blood supply
Elastic Connective Tissue
• Primarily elastin fibers
• Walls of large arteries
• Alveoli of lungs
Bone
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•
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•
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support - for muscles, organs, and soft
tissues
leverage and movement - the synovial
joints
protection - for critical organs
calcium phosphate storage - mineral
balance
hemopoiesis - formation of blood cells
Compact Bone
• Compact bone is a very dense tissue forming the outer
layer of all bones and the thickened shafts or diaphyses
of long bones. In a microscopic view, compact bone
always contains numerous osteons or Haversian
Systems. Each consists of a central canal through which
blood vessels and nerves pass. Surrounding this canal
are multiple concentric lamellae or layers of bone.
Haversian systems are only found in compact bone.
Their specific arrangements within compact bone
contribute to the strength of this osseous tissue type.
Spongy bone
• Cancellous or bone is found forming the core of most flat
and irregular bones. It is also very prevalent in the
epiphyses(ends) of long bones. The construction of this
osseous tissue type is quite different than that of
compact bone. One key difference is the absence of
osteons! Spongy bone as the name implies is more
open and in cross-section offers a compartmentalized
appearance not unlike that of a sponge. Consisting of
interconnecting "struts" of bone called trabeculae,
spongy bone has abundant spaces typically occupied by
bone marrow and adipose tissues.
Spongy bone
Cartilage
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Protein-carbohydrate matrix
More water than bone
No Calcium salts
Firm, smooth, flexible
Chondrocytes nourished by diffusion
Repair very slow if at all
Muscle Tissue
• Specialized for contraction
• Three types
– Skeletal
– Smooth
– Cardiac
Skeletal
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AKA: Striated, voluntary
Cylindrical cells
Have several nuclei
Appear striated or striped
Attach to bones
Produce heat
Skeletal muscle is the most abundant
muscle type in the body.
Smooth Muscle
• Involuntary or visceral muscle
• Cells have tapered ends
• Functions of organs
Cardiac
• Only in the heart
• Branched with one nucleus each
• Cell membranes folded and lock cells
together
• Forms the myocardium
• Inherent ability to beat
• What are the other names for skeletal muscle
and smooth muscle?
• Which type of muscle tissue must receive nerve
impulses to contract?
• What movement does cardiac muscle produce?
Nerve Tissue
• Neurons
• Two divisions classically named
– CNS: brain and spinal cord
– PNS
• Neurons capable of transmitting impulses
Neuron Structure
• In which direction do the dendrites and
axon carry impulses?
• What is the name for the space between
two neurons?
Membranes
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Sheets of tissues
Cover or line surfaces
Separate organs
May produce secretions
Two main categories
– Epithelial
– Connective tissue
Epithelial Membranes
• Two divisions
– Serous
• Produces serous fluid
– Mucous
• Produces mucus
Mucous membranes line the
digestive,
respiratory, urinary, and
reproductive tracts.
• Serous membranes occur in
pairs, with a
parietal and visceral layer.
• The heart also has a set of serous
membranes,
the parietal and visceral
pericardia.
Serous Membranes
• Simple squamous epithelium
• Line some closed body cavities
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Pleural membranes: thorax
Parietal pleura: line chest wall
Visceral pleura: cover lungs
Parietal pericardium: lines pericardium
Visceral pericardium: covers heart
Peritoneum lines abdominal cavity
Mesentery or visceral peritoneum covers abdominal
organs
• Serous fluid prevents friction
Mucous Membranes
• Line body tracts
– Respiratory
– Digestive
– Urinary
– Reproductive
• Mucus keeps epithelial cells wet
• What is the function of serous fluid?
• What is the function of mucus?
• What do the mucous membrane tracts all
have in common?
Connective Tissue Membranes
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Superficial fascia
Periosteum
Perichondrium
Synovial
Deep fascia
Meninges
Fibrous pericardium